@@ -49,12 +49,14 @@ static int sysclient = -1;
/* port id numbers for this client */
static int announce_port = -1;
+/* number of subscriptions to announce port */
+static int announce_subscribed;
/* fill standard header data, source port & channel are filled in */
static int setheader(struct snd_seq_event * ev, int client, int port)
{
- if (announce_port < 0)
+ if (announce_port < 0 || !announce_subscribed)
return -ENODEV;
memset(ev, 0, sizeof(struct snd_seq_event));
@@ -104,6 +106,22 @@ static int event_input_timer(struct snd_seq_event * ev, int direct, void *privat
return snd_seq_control_queue(ev, atomic, hop);
}
+static int sys_announce_subscribe(void *private_data,
+ struct snd_seq_port_subscribe *info)
+{
+ announce_subscribed++;
+ return 0;
+}
+
+static int sys_announce_unsubscribe(void *private_data,
+ struct snd_seq_port_subscribe *info)
+{
+ if (snd_BUG_ON(!announce_subscribed))
+ return 0;
+ announce_subscribed--;
+ return 0;
+}
+
/* register our internal client */
int __init snd_seq_system_client_init(void)
{
@@ -143,7 +161,10 @@ int __init snd_seq_system_client_init(void)
/* register announcement port */
strcpy(port->name, "Announce");
port->capability = SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ; /* for broadcast only */
- port->kernel = NULL;
+ pcallbacks.event_input = NULL;
+ pcallbacks.subscribe = sys_announce_subscribe;
+ pcallbacks.unsubscribe = sys_announce_unsubscribe;
+ port->kernel = &pcallbacks;
port->type = 0;
port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
port->addr.client = sysclient;
The notification via system announce port isn't a lightweight task, hence it'd be better to skip if there is no subscription is done for the announce port. Implement a simple counter for checking that by hooking the subscribe and unsubscribe callbacks. Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/core/seq/seq_system.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-)